Novel Programming Features Help Alleviate Subthalamic Nucleus Stimulation‐Induced Side Effects

Background: Subthalamic nucleus deep brain stimulation (STN‐DBS) is a widely used treatment for Parkinsonʼs disease (PD) patients with motor complications, but can result in adverse effects (AEs) in a significant proportion of treated patients. The use of novel programming features including short pulse width (PW) and directional steering in alleviating stimulation‐induced AEs has not been explored. / Objective: To determine if programming with short PW, directional steering, or the combination of these novel techniques can improve stimulation‐induced dysarthria, dyskinesia, and pyramidal AEs. / Methods: Thirty‐two consecutive PD patients who experienced reversible AEs of STN‐DBS had optimization of their settings using either short PW, directional steering, or the combination, while ensuring equivalent control of motor symptoms. Pairwise comparisons of pre‐ and post‐optimization adverse effect ratings were made. Patients were left on the alternative setting with the greatest benefit and followed up at 6 months. Modeling of volume of tissue activated (VTA) and charge per pulse (Qp) calculations were used to explore potential underlying mechanisms of any differences found. / Results: There were significant improvements in stimulation‐induced dysarthria, dyskinesia, and pyramidal side effects after optimization. At 6 months, mean AE ratings remained significantly improved compared to pre‐optimization ratings. Different patterns of shift in VTA for each AE, and Qp could be used to explain improvements using novel techniques. / Conclusions: Stimulation‐induced dysarthria, dyskinesia, and pyramidal AEs induced by STN‐DBS can be improved by using novel programming techniques. These represent additional tools to conventional methods that can be used to address these AEs

Short Versus Conventional Pulse-Width Deep Brain Stimulation in Parkinson's Disease: A Randomized Crossover Comparison

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN-DBS) is an effective therapy for selected Parkinson's disease patients with motor fluctuations, but can adversely affect speech and axial symptoms. The use of short pulse width (PW) has been shown to expand the therapeutic window acutely, but its utility in reducing side effects in chronic STN-DBS patients has not been evaluated. OBJECTIVE: To compare the effect of short PW settings using 30-μs with conventional 60-μs settings on stimulation-induced dysarthria in Parkinson's disease patients with previously implanted STN-DBS systems. METHODS: In this single-center, double-blind, randomized crossover trial, we assigned 16 Parkinson's disease patients who had been on STN-DBS for a mean of 6.5 years and exhibited moderate dysarthria to 30-μs or 60-μs settings for 4 weeks followed by the alternative PW setting for a further 4 weeks. The primary outcome was difference in dysarthric speech measured by the Sentence Intelligibility Test between study baseline and the 2 PW conditions. Secondary outcomes included motor, nonmotor, and quality of life measures. RESULTS: There was no difference in the Sentence Intelligibility Test scores between baseline and the 2 treatment conditions (P = 0.25). There were also no differences noted in motor, nonmotor, or quality of life scores. The 30-μs settings were well tolerated, and adverse event rates were similar to those at conventional PW settings. Post hoc analysis indicated that patients with dysarthria and a shorter duration of DBS may be improved by short PW stimulation. CONCLUSIONS: Short PW settings using 30 μs did not alter dysarthric speech in chronic STN-DBS patients. A future study should evaluate whether patients with shorter duration of DBS may be helped by short PW settings. © 2019 International Parkinson and Movement Disorder Society